The great significance of the Gettysburg Address, then, “is that it restates and reaffirms another great expression of the American mind, the Declaration of Independence—the opening “Four score and seven years,” in fact, points directly to the year 1776. There is one important difference, however, between our foundational political document and the Gettysburg Address: the Declaration of Independence asserts the “self-evident” truth that “all men are created equal,” whereas Lincoln refers to human equality as a “proposition.” What was self-evidently true to the men of 1776 had been challenged and even rejected by later generations, leading to a renewed defense of slavery, the great sectional divisions within the Union, and the hostilities then engulfing the nation. Likening the nation’s founding principle to a mathematical theorem, Lincoln suggests that the truth of this “proposition” is not immediately self-evident for all, but must be demonstrably proven to be true.” historyplex “By insisting that…